With continuing emphasis being placed upon the improvement of safety conditions in relation to the use of chain saws, it has become increasingly important to protect chain saw operators from injuries resulting from "kickbacks" of chain saws or from situations where operators losing their grip on chain saw handles such that their hands are brought into engagement with chain saw cutter chains.
Several techniques have been developed in the past in an endeavor to improve chain saw safety and protect operators from injuries when events such as this occur.
All this notwithstanding, there has persisted in the art a need to improve the efficiency and reliability of such safety mechanisms.
Accordingly, it is a specific object of the present invention to provide a chain saw safety brake which is snap-acting and operated via an accelerating mechanism so as to produce a cutter chain braking action in an extremely rapid manner.
It is a further object of the present invention to accomplish such a rapidity of breaking with a minimized movement of an actuating member or safety handle.
Yet another object of the invention is to provide a chain saw safety brake actuating mechanism wherein an intensified biasing force is created when the actuating mechanism is moved to a brake actuating position.
It is likewise an object of the invention to provide such improvements in the art as heretofore described concurrent with the attainment of relative structural simplicity and reliability and the minimizaton of alterations to conventional chain saw structures.
In accomplishing at least some of these objectives, the present invention contemplates a method of actuating a chain saw safety brake which is characterized as follows.
The method of this invention involves the safety braking of a chain saw which includes brake means and brake actuating means movably engaged with said brake means. The inventive method entails:
Operably interposing actuation accelerator means between the brake actuating means and the brake means and employing this accelerator means to effect a faster rate of brake actuation than would result from said movable engagement between the brake actuating means and the brake means; PA1 Biasing the brake actuating means toward a nonactuating position with a relatively lower biasing force; and PA1 Biasing the brake actuating means toward an actuating position with a relatively higher biasing force.
Likewise, the invention contemplates unique combinations of apparatus means which coact to effect the method steps heretofore described.
Moreover, the invention herein presented contemplates a variety of structural embodiments characterized by a resiliently biased, snap-acting, over-center actuating mechanism.
In describing the invention, reference will be made to these presently preferred embodiments by way of example and with reference to appended drawings. However, it will be understood that the reference to preferred embodiments will be by way of example only and not by way of restricting the scope of the present invention.